The invention relates to systems for providing desired temperature throughout the interior of an automobile.
The invention allows for cooling and heating passengers in the rear seats in a motor vehicle without requiring an auxiliary evaporator. In most vehicles today, passengers in the back seat are cooled by: a) air from the front registers; or b) air from the front end evaporator ducted to the back seat; or c) an auxiliary evaporator with dedicated thermal expansion valves and blower.
In this invention, the above three systems are improved, through the use of a liquid anti-freeze such as glycol flowing in a pipe line (hard or bendable) which is cooled by a refrigerant stream or heated by the engine block and routed to the rear seat area. Small heat exchangers with dedicated fans will allow each rear seat passenger to control the comfort level in the immediate environment.
The following prior art patents relate to this field but do not teach the improvement achieved by this invention: 3,753,462; 3,999,598; 4,724,898; 5,048,299; and 5,904,052.
The system of this invention uses a heat transfer fluid, preferably the same fluid as used in the engine coolant, namely, a mixture of water and glycol anti-freeze. The stream of the heat transfer fluid can be either hot because it comes from the engine or cooled by an air conditioning heat exchanger before being routed to the rear of the vehicle. Rear seat passengers will then have control of the thermal comfort in their zone.
Anti-freeze, namely a mixture of ethylene glycol and water (referred to in this specification as xe2x80x9canti-freezexe2x80x9d or xe2x80x9cglycolxe2x80x9d), can be used in small tubing which is much more compact than the ducts used currently for air flow. The tubing carrying the liquid anti-freeze is in interface with heat exchangers that are packaged in a variety of locations. Thus, cooling is provided without bulky air flow ducts to the rear of the vehicle and without requiring expensive high pressure refrigerant circuit tubing plumbed into the rear compartment area of the vehicle.
Cooling of the glycol may take place in the refrigerant line after the air conditioning system evaporator or within the evaporator (in terms of refrigerant flow). This packaging arrangement reduces the potential for thermal stratification in the evaporator due to the super heat region. In the rear of the vehicle, the glycol tubing can be delivered to one or more heat exchangers. For a simple multi-zone system, only one rear heat exchanger is required. However, there is the option to add as many heat exchangers as feasible to reach optimum passenger comfort.
Other general and more specific aspects of this invention will be set forth in the ensuing description and claims.